Why are the recommendations so different between my marketplaces?

They are genuinely different markets. Prices differ, competitors differ, conversion rates differ, and a thinner marketplace accumulates evidence more slowly, so it needs a longer Decision window to reach the same confidence.

That is why a term negated in one may still be running in the other: it may not have cleared the click bar there yet, or it may actually be converting.

Each marketplace is judged only on its own evidence, in its own currency.